Does perceptual high variability phonetic training improve L2 speech production? A meta-analysis of perception-production connection

This meta-analysis of 31 studies aimed to determine the effectiveness of perception-based high variability phonetic training (HVPT) for second language (L2) production learning and to identify learner-related and methodological variables that influence production gains. Based on independent effect sizes for 43 within-participant and 17 between-participant designs, small-to-medium effects of post-training improvement were found. The average production gains for trained items and untrained items were 10.50% and 4.50%, respectively. Neither strong support for long-term retention of production learning nor generalization to untrained stimuli was observed, however. Moderator analyses showed that post-training production gains were influenced by a number of factors related to learner profiles (age and learning context), training features (provision of phonetic information, training duration, and training time per session), and features of production tests (elicitation tasks, prompt modality, and outcome measures). The relationship between perception and production gains was negligible at the participant level, but was significant and moderate at the level of individual studies for post-training and retention data. These findings provide partial support for a perception-production link. This study makes several recommendations for future studies investigating the effects of HVPT on L2 speech production learning.